I would like to help ensure data cleanliness and consistency in our database, and wanted to see what suggestions were out there as to how best to do that so that I only remove emails that are actually invalid (junk, mailbox no longer exists, etc.). I am hoping that this will improve our delivery and open/click rates as a result of not sending to emails that are never going to open an email!

The intention is to first remove these from any email and/or nurture programs that they belong to, and then into a quarantine so that the decision whether to completely remove them from our database (Marketo and SFDC) can be made at a later date. The intention behind the quarantine is to ensure that we are potentially giving leads a chance to "wake up" if there is the possibility of doing that, and also to have a chance to check the data before it is removed completely.

To get an idea of where are invalid emails might be sitting, I have pulled the following Smart Campaigns:

The flow for whichever one we use will be to move them into an inactive stream/list and remove them from whatever program they are in.

I am assuming that there will be crossover between many of these campaigns, so, in order to achieve the above desired outcome, is there one or more campaigns that would give me the best results? Is there one that I am missing? If there are multiple items that should be considered the I can create a single campaign with everything in the smart list.

Any insight, suggestions, etc. are welcome and much appreciated as always!

You mentioned don't expect invalid emails to come back to life, but is it possible for invalids to change from TRUE to FALSE? I created a cleanup smart campaign yesterday and today the number of qualified leads has decreased. Would you recommend a certain about of time a lead should be invalid before removing from database?